It is known to use a 3D scanner to create a 3D image of a scene, e.g. the inside of a factory or a room in a nuclear power plant.
Base members are attached to various elements (walls, floor, ceiling etc.) of the scene before the 3D scanning is carried out and reference members, e.g. 3D reference spheres, are removably attached to the base members. Each reference member is adapted to cooperate with the 3D scanner to determine the position of a reference point associated with the base member to which the reference member is attached. This means that each base member is associated with a reference point.
The 3D scanner is positioned at several locations, strategically chosen so that every element within the scene is covered, and for each of these locations a data acquisition process is carried out. Each acquisition process results in a point cloud that represents the part of the scene visible from the corresponding location. Some of the points in the point clouds correspond to the reference points associated with the base members and this information is used to merge said point clouds into a single point cloud that represents the entire scene.
It is also known to determine the coordinates of the reference points associated with the base members in a geodetic frame.
For this purpose, a different type of reference member, e.g. a prism or a reflector, is attached to the base members and standard surveying equipment, e.g. a total station, is used to determine the coordinates of the reference points in the geodetic frame.
Information related to each base member is stored in a database. Suitable information is, for example, which type of element (door, window, closet etc.) the base member is connected to, the dimensions of the element and the coordinates of the reference point of the base member. Each base member has an identification number (usually written on a plaque located next to the base member) and this identification number can be used to access the information stored in the database.
A user with access to the database may use the stored information, for example, to create an accurate 3D image of the scene and to acquire specific information relating to each element and base member.